Evolution of Humankind

Lessons

Senior 1 · History and Citizenship

Evolution of Humankind

5 lessons

Lesson 2 of 5

Stages in the evolution of humankind

25 min

Read the chart

This chart shows six kinds of hominid known from fossils. Each bar runs from the oldest to the youngest fossil of that species found so far. Study it and answer the questions below it before you read on.

Figure 2. When six hominid species lived, based on the fossils found so far, with three turning points in toolmaking and the use of fire. Drawn by Ganzaa from dates published by the Smithsonian Human Origins Program.

Which is the oldest species on the chart?
Name two species that were alive at the same time as Homo erectus.
Roughly how long has our own species, Homo sapiens, existed?

Definition

Species: a group of living things that are alike and can breed with one another. Scientists give each species a two-part Latin name: the genus (Homo) and the species (sapiens).

Definition

Bipedalism: walking upright on two legs. It is the first feature that marks the human family apart from other apes. Example: "Lucy" was bipedal, as her knee and hip bones show.

Definition

Homo sapiens: "wise human", the species to which all people alive today belong. It appeared in Africa about 300,000 years ago and later spread to every continent.

The main stages

Species (meaning)	When it lived	Brain size	Key features and tools	Famous fossil
Australopithecus afarensis ("southern ape from Afar")	c. 3.9 to 2.9 million years ago	$385$ to $550\,\mathrm{cm^3}$	walked upright but also climbed trees; about 1.1 m tall; no stone tools known for certain	"Lucy", Hadar, Ethiopia (1974)
Homo habilis ("handy man")	c. 2.4 to 1.4 million years ago	$550$ to $690\,\mathrm{cm^3}$	larger brain, smaller teeth; made simple Oldowan choppers	Olduvai Gorge, Tanzania (named 1964)
Homo erectus ("upright man")	c. 1.9 million to 110,000 years ago	$550$ to $1250\,\mathrm{cm^3}$	human body shape, long legs; made hand-axes; used fire; first to spread out of Africa into Asia	"Turkana Boy", Kenya (1984)
Homo neanderthalensis ("man from the Neander valley")	c. 400,000 to 40,000 years ago	$1170$ to $1740\,\mathrm{cm^3}$	lived in Europe and western Asia; strong, adapted to cold; fine stone tools, fire, burials	Neander valley, Germany (1856)
Homo sapiens ("wise human")	c. 300,000 years ago to today	about $1350\,\mathrm{cm^3}$ on average	high rounded skull, small face; blade tools, art, ornaments, language; spread worldwide	Jebel Irhoud, Morocco; Omo, Ethiopia

Other hominids lived alongside these, such as Paranthropus boisei, a hominid with huge jaws and teeth for chewing tough plants, found at Olduvai. The picture is a branching bush, not a single line: several kinds of hominid often lived at the same time, and most branches died out.

Worked example: using the table to compare

Question 1: About how many times larger is the average modern human brain than the largest brain of Australopithecus afarensis?

Take the two values from the table: $1350\,\mathrm{cm^3}$ and $550\,\mathrm{cm^3}$ .
Divide: $\frac{1350}{550} \approx 2.5$
Answer: about two and a half times larger. (Against the smallest afarensis brain, $\frac{1350}{385} \approx 3.5$ times.)

Question 2: How long did Homo erectus survive, and how does that compare with the time Homo sapiens has existed so far?

Work in millions of years: $1.9 - 0.11 = 1.79$ million years for Homo erectus.
Homo sapiens has existed for about $0.3$ million years.
Compare: $\frac{1.79}{0.3} \approx 6$
Answer: Homo erectus lasted about six times longer than our species has existed so far: one of the most successful hominids ever.

Warning

The "march of progress" picture is wrong. Posters showing an ape turning step by step into a man suggest a single ladder with a goal. In fact evolution branched: Paranthropus, Homo erectus and the Neanderthals were not failed attempts at being us, but successful species in their own times and places.

Case study: the Turkana Boy, Kenya

In 1984 the Kenyan fossil hunter Kamoya Kimeu spotted a small piece of skull on a slope at Nariokotome, west of Lake Turkana. Over the next years his team, working with the Leakey family, uncovered almost the whole skeleton of a young Homo erectus who died about 1.5 million years ago. It is one of the most complete early human skeletons ever found.

The skeleton showed that Homo erectus already had long legs and a body shaped like ours, built for walking and running long distances in open grassland. The boy, aged between about 8 and 12 when he died, was already about 1.6 m tall. His skeleton is kept at the National Museums of Kenya in Nairobi.

PBS Eons: "The Humans That Lived Before Us". Listen for why scientists keep adding species to the genus <em>Homo</em>, and note two species that are not in the table above.

Tip

Memory hook: the Latin names tell the story. Habilis is "handy" (tools), erectus is "upright" (long legs, travel), sapiens is "wise" (art, language). Order: Australopithecus, then Habilis, Erectus, Sapiens: "A Happy Elephant Sings".

Discussion

Group task: A poster in a shop shows five figures in a line, from a stooping ape to a modern man carrying a spear. Using Figure 2 and the warning box, list three things that are misleading about the poster. Then sketch a better diagram.

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Practice

What is bipedalism, and why is it important in the story of human evolution?
Put these in order, oldest first: Homo sapiens, Australopithecus afarensis, Homo erectus, Homo habilis.
Which hominid species was the first to spread out of Africa?
Using the table, name the species whose fossils include "Lucy", and the country where she was found.
The average modern brain is about $1350\,\mathrm{cm^3}$ and a large Homo habilis brain about $690\,\mathrm{cm^3}$ . About how many times larger is the modern brain? Show your working.
Why do scientists describe human evolution as a "bush" rather than a "ladder"?
Who found the Turkana Boy, and what did the skeleton show about Homo erectus?

Show answersHide answers

Walking upright on two legs. It is the first feature that marks the human family apart from other apes, and it freed the hands for carrying and toolmaking.
Australopithecus afarensis, Homo habilis, Homo erectus, Homo sapiens.
Homo erectus, about 1.8 million years ago.
Australopithecus afarensis; Ethiopia (Hadar, 1974).
$\frac{1350}{690} \approx 2$ : about twice as large.
Because several species lived at the same time, lines branched off and most died out; there was no single straight line leading to modern humans.
Kamoya Kimeu, in 1984, at Nariokotome near Lake Turkana, Kenya. It showed that Homo erectus had long legs and a body shaped like ours, suited to walking long distances.

Sources and credits

Photo: Niño de Turkana - Museo Nacional de Nairobi, ProtoplasmaKid, via Wikimedia Commons, CC BY-SA 4.0.
Figure 2 and the table were drawn and written by Ganzaa. Dates and brain sizes follow the species pages of the Smithsonian Human Origins Program (facts only; no text copied).
Video: "The Humans That Lived Before Us", PBS Eons, embedded from YouTube.
The rest of this lesson, the practice items and the unit exercises were written by Ganzaa.

This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.

1Read the chart

2The main stages

3Case study: the Turkana Boy, Kenya

4Discussion

Read the chart

The main stages

Case study: the Turkana Boy, Kenya

Discussion